No - this should just work when you select PC from the Beo4 LIST. Have you tried the audio extractor output into another amp to check that it is working?

EDIT: Do you mean the red/white connectors in the CAMERA panel just behind the top left of the screen (with a separate yellow connector for video)? This is incorrect - there are other PC audio inputs in the main connection panel in the back.

Will try to connect to an amplifier to see if the HDMI boks audio out is working - or maybe I could just connect to camcord and select that source for the audio test - but they maybe is mutes due to not sync.

The one I have looks like this one :https://www.amazon.co.uk/ViewHD-Audio-Extractor-Converter-Model/dp/B00KBHX072?pd_rd_wg=6uFXt&pd_rd_r=795e95e4-8135-4f3f-a391-3631cae37d0c&pd_rd_w=6AwYn&ref_=pd_gw_simh&pf_rd_r=PS3JZGX2JWR9AAB1S3AD&pf_rd_p=14f91171-0541-58ad-938b-3aec945f4cb7

Talked to a fried that suspects it is a EDID problem, that the TV answers back to the AppleTV that it do not support audio, and the Apple TV mutes - so think I need to find a HDMI converter with EDID manager/support. -